WO 2011/036634 A1 discloses a biosensor system comprising a biosensor cartridge with a sensor surface and first and second optical detection systems for detecting particles on the sensor surface. The first optical detection system is adapted to detect the particles by detecting intensity changes of reflected light, which has been reflected at the sensor surface, wherein the intensity changes are based on frustrated total internal reflection (FTIR). The second optical detection system is adapted to detect the particles by detecting light scattered by the particles.
JP 2008 058249 A discloses an apparatus and a method for viewing photometry. The apparatus comprises an observation system for observing an image of a sample and a photometry system that measures the strength of the light from the sample. Light from a lamp source illuminates a pinhole, and an image of the pinhole is projected on the bottom side of the sample via an optical path switching unit. Light reflected by the sample enters the switching unit again. A part of this light passes the switching unit and is detected on an imaging surface, and a further part is reflected in the switching unit and focused on a photodetector. In addition, the apparatus comprises a further light source device for illuminating the upper side of the sample for bright-field observation. Light transmitting the sample travels through the switching unit to the imaging surface.